/*
 * Copyright 2002-2009 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.org.rapid_framework.generator.util;

import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Package-protected helper class for {@link AntPathMatcher}. Tests whether or not a string matches against a pattern
 * using a regular expression.
 *
 * <p>The pattern may contain special characters: '*' means zero or more characters; '?' means one and only one
 * character; '{' and '}' indicate a URI template pattern.
 *
 * @author Arjen Poutsma
 * @since 3.0
 */
class AntPathStringMatcher {

    private static final Pattern GLOB_PATTERN = Pattern.compile("\\?|\\*|\\{([^/]+?)\\}");

    private static final String DEFAULT_VARIABLE_PATTERN = "(.*)";

    private final Pattern pattern;

    private String str;

    private final List<String> variableNames = new LinkedList<String>();

    private final Map<String, String> uriTemplateVariables;

    /** Construct a new instance of the <code>AntPatchStringMatcher</code>. */
    AntPathStringMatcher(String pattern, String str, Map<String, String> uriTemplateVariables) {

	this.str = str;
	this.uriTemplateVariables = uriTemplateVariables;
	this.pattern = createPattern(pattern);
    }

    private Pattern createPattern(String pattern) {

	StringBuilder patternBuilder = new StringBuilder();
	Matcher m = GLOB_PATTERN.matcher(pattern);
	int end = 0;
	while (m.find()) {
	    patternBuilder.append(quote(pattern, end, m.start()));
	    String match = m.group();
	    if ("?".equals(match)) {
		patternBuilder.append('.');
	    } else if ("*".equals(match)) {
		patternBuilder.append(".*");
	    } else if (match.startsWith("{")&&match.endsWith("}")) {
		int colonIdx = match.indexOf(':');
		if (colonIdx==-1) {
		    patternBuilder.append(DEFAULT_VARIABLE_PATTERN);
		    variableNames.add(m.group(1));
		} else {
		    String variablePattern = match.substring(colonIdx+1, match.length()-1);
		    patternBuilder.append('(');
		    patternBuilder.append(variablePattern);
		    patternBuilder.append(')');
		    String variableName = match.substring(1, colonIdx);
		    variableNames.add(variableName);
		}
	    }
	    end = m.end();
	}
	patternBuilder.append(quote(pattern, end, pattern.length()));
	return Pattern.compile(patternBuilder.toString());
    }

    private String quote(String s, int start, int end) {

	if (start==end) {
	    return "";
	}
	return Pattern.quote(s.substring(start, end));
    }

    /**
     * Main entry point.
     *
     * @return <code>true</code> if the string matches against the pattern, or <code>false</code> otherwise.
     */
    public boolean matchStrings() {

	Matcher matcher = pattern.matcher(str);
	if (matcher.matches()) {
	    if (uriTemplateVariables!=null) {
		for (int i = 1; i<=matcher.groupCount(); i++) {
		    String name = this.variableNames.get(i-1);
		    String value = matcher.group(i);
		    uriTemplateVariables.put(name, value);
		}
	    }
	    return true;
	} else {
	    return false;
	}
    }

}
